There are a certain number of difficulties in operating a passive radar system comprising a plurality of transmitters and/or receivers. In effect, each transmitter-receiver pair constitutes a bistatic base from which it is possible to perform, in different simple and known manners, the bistatic detection and tracking of objects moving in the space covered by that base.
However, when the aim is to know the overall aerial situation of the area covered by the radar system, it is necessary to jointly analyse the information delivered by the different bistatic bases, generally analysed in the form of individual tracks, so as to merge this information to construct global tracks or merged tracks.
A joint analysis of the information produced by the different bistatic bases consists in practice in forming and maintaining global Cartesian tracks by associating the detection information, the bistatic blips, produced by the different bistatic bases forming the detection system concerned, to form and maintain Cartesian tracks.
The French patent application document filed by the applicant on Jan. 9, 2009, under the number 0904144, describes a method that allows for such a joint analysis. This method is illustrated by FIG. 1. The method described makes it possible to form Cartesian tracks from bistatic blips produced by distinct bistatic bases, in the context of a detection system comprising a number of receivers, two bistatic bases then being able to be formed by the same receiver or by different receivers.
As FIG. 1 illustrates and as the text of the abovementioned patent application mentions, the formation and maintenance of these Cartesian tracks naturally involves one or more initialization steps. Various known methods can be used to perform the initialization of Cartesian tracks from bistatic blips produced by the different bistatic bases, formed from different receivers.
These methods are generally intimately linked, in respect of their principle, to the structure of the system concerned, and to the manner in which the bistatic blips produced by the different bistatic bases are associated.
However, whatever the method used, the initialization of Cartesian tracks comes up against the difficulty that is how to take into account a very large number of bistatic blips available at each instant to try to initialize tracks.